The present invention relates to a transmission belt.
A conventional transmission belt is disclosed in JP No. 56-156539. It comprises a first column of link plates, a second column of link plates, a plurality of load blocks arranged one behind another, and a plurality of joint pins, each interposed between the adjacent two load blocks. The link plates in the first column are linked by the joint pins to form a first chain, while the link plates in the second column are linked by the same joint pins to form a second chain. The load blocks have first and second chain receiving cutouts which the first and second chains are positioned in. In assembly, with a load block interposed between them, two joint pins have one end inserted into two pin holes formed through a link plate positioned in one chain receiving cutout of the load block and opposite ends inserted into two pin holes formed through another link plate positioned in the opposite chain receiving cutout of the load block, thereby forming a basic unit. Subsequently, a plurality of such basic units are assembled one behind another with a load block interposed therebetween. This load block interposed between the adjacent two basic units is locked in position between the adjacent two basic units by interconnecting the joint pins of the adjacent two basic units by two link plates positioned in one and opposite chain receiving cutouts of the load block.
This conventional transmission belt poses a problem that it requires tedious manual work in assembly which is quite difficult to convert into automation, and thus making mass production is impossible.
Another problem of this conventional transmission belt is that each of the load blocks has a pillar portion positioned between the one and opposite chain receiving cutouts which is subject to excessive stress during transmission of power by the belt since the transmission of power between the adjacent load blocks is performed by a joint pin interposed therebetween. Thus, the load blocks used in this conventional transmission belt cannot enjoy sufficiently long service life since it is difficult to strengthen the pillar portion that has a limited width between the one and opposite chain receiving cutouts.
An object of the present invention is to provide a transmission belt which is easy to assemble, which can be manufactured by automation, and which has a sufficiently long service life.